Device insuring in alpha continuous and automatic manner the synchronism between alpha gramophone and alpha cinematographic projection machine



Jan. 1, 1929'.

DEVICE INSURING IN A CONTIN BETWEEN A GRAMOIHONE AND Filed July 25,-1924 L. ROBIMARGA UOUS AND AUTOMATIC MANNER THE SYNCHRONISM 'ACINEMATOGRAPHIC PROJECTION MACHINE 2 Sheets-Sheet 1 IN vflvrok Z 471ohmalya ATI'Ok/VEYS Jan. 1, 1929. 1,697,695

L. ROBIMARGA DEVICE INSURING IN A CONTINUOUS AND AUTOMATIC MANNER THESYNCHRONISM BETWEEN A GRAMOPHONE AND A CINEMATOGRAPHIC PROJECTIONMACHINE Filed July 23; 1924 I 2 Sheets-Sheet 2 A TTORNE VS Patented Jan.1, 1929 LUIGI ROBIMARGA,

1,697,695 PATENT OFFICE.

OF MILAN, ITALY.

' DEVICE ENSURING IN A CONTII TUOUS AND AUTOMATIC MANNER TEE SYNCHRONISMBETWEEN A GRAMOPHONE AND A CINEMATOGEAPHIC PROJECTION MACHINE.

Application filed July 23, 1924, Serial No. 727,785, and in Italy July26, 1928.

This invention concerns a device insuring the synchronism in themovement of a gramophone to be driven together with a cinematographicprojection machine for the pur- '5 pose of giving the phoneticalreproduction accompanied by the optical reproduction of a movingpicture. Many such devices have already been suggested in order to solvethis problem, but, as a rule, they only allow the 1 operator tocompensate a phase discordancein the machines when it has already beenveri fied and the operator himself has-perceived it.

The object of the invention instead is to prevent any noticeablediscordance from aris- 1 ing-and to eliminate the slight discordanceswhich may occur from time to time, on' account of perturbing causes.

For this purpose on the transmission of.

the movement to one of the two machines,

' 2 preferably of the projection machine, a

change speed gear is provided allowing twospeeds almost alike, the lowerof said speeds being less than the lowest speed allowable by the motorto the gramophone machine and the higher being greater than the highestspeed. allowed by themotor to the gramophone. '1

Said device with'double gear ratio is periodically controlled 'in itsworking, at short -3 intervals of time, at the end'ofeach one of them anautomatic switch enters into action leaving unchanged the connectionif'both machines are in phase concordance and causes it'instead to passfrom the higher to'theilower 3|. ratio or from the lower to the higherratio if the cinematographic. machine is lagging -behind or runningahead. 4

In this way the speed is continuously adjusted and it is notpossible forthe phase discordance to reach appreciable values.

' In the drawing which serves ,to illustrate the synchronism regulatoraccording to thisinvention: 1 ig. 1 shows a top'view of the complete ap-5 paratus adapted to be connected with the projection machine; I

F ig. 2 is a vertical section of the same according to line X X 'of Fig..1. Fig. 3 is a detail of Fig. 2. A

'Fig. 4 is a view of the electrical con nections of the'apparatus with atwo disc gram'ophonical machine.

In the several figures of the drawing the Same reference numerals areused-to indi l .cate correspondmgparts.

As it may be seen from the drawing the apparatus mcludes a generalfoundation p ate 1 upon which are suitable sup orts 2, 3. In thesupports 2 is mounted a s aft 4 to which, by means of a pulley 5 onwhich runs a belt 6 is imparted the movement by the electrical motorwhich drives the whole plant and in the supports 3 is mounted a shaft 7which sets into motion the projection machine notshown in the drawing,and bears a little.;fly-wheel 8.

Bothshafts 4 and 7 are connected together by means ofthe double speedgear built in the following manner. Upon supports 9 is rotatably mountedva shaft 10 upon which are keyed a toothed wheel 11 and a pinion 12. Thetoothed wheel meshes with a pinion 13 borne by the shaft 7 aforesaid:the pinion 12 meshes with a toothed wheel 14 keyed u on a shaft 15carried by a support 16 an connected with a hand 17 running upon a dial18, which'will' be described hereinafter.

- Upon the shaft 10 are besides mounted loosely the two toothed Wheels19 and 20 respectively gearing with the pinions 21 and 22 of differentdiameters both keyed on the shaft 4.

With the wheel '19 is connected and made integral with it, a ratchetwheel 23 on whose teeth rests, pressed by a spring 24, a lever 25revolving around a pivot 26 fastened u on a disc 27 also loose on theshaft 10; in i 1 the lever 25has been omitted in order to et- I ter showthe underlying ratchet wheel 23. 90 The lever 25 rests upon the crown ofthe wheel 23 with a tooth 28 forming a ratchet coupling for. the wheel19,.and the disc 27, such that the wheel 19, by means of the wheel 23which is integral with it, carries in its movement the disc 27 when thewheel turns in the direction shown'by the arrow z. The disc 27, on theface opposite to that on which is mounted the lever 25, bears a tooth29'which meets with a similar tooth 3Q projecting from that face of thewheel 11 which is turned towards disc 27. When both teeth 29, 30 are incontact, and the wheel 19 turns in the direction of the arrow e, thewheel 11 is carried in the movement ofwheel 19 and turns together withit. v c

The same wheel 11, on its opposite face, turned towards the wheel 20,bears a crown gear 31 on which ride two teeth 32 projecting from'theface of the wheel 20 each of said 1 1 teeth passing through the wheel 20and being connected. at 33' with a spring 33 which is tures.

fastened to the left side of the wheel 20 and tends to keep the teeth32. pressed against the said crown. The shape of the crown gear 31 issuch that when the wheels 11 and 20 turn both in the same direct-ion asshown by arrow .2 and the wheel 11 moves at a higher speed than thewheel 20, it lags behind while ,the teeth 32 ride upon the crown 31. Ifinstead the connection between the wheel 19 and the disc 27 is severedand the tooth 29 does not carry along the tooth 30 then the teeth 32cause the wheel 11 to advance at the same speed of the wheel 20.

Theconnection between the wheel 19 and the disc 27 may be severed in thefollowing manner.

A spindle 34 carried by supports 35 bears on one ofits endsa'tooth 36and on the other end the armature. 37 of an electro-magnet 38, and by aspring 39 which is coiled around it is continually pushed to take .theposition shown in the drawing, wherein the tooth 36 is placed in the wayof the lever 25, in such manner that the latter turning together withthe disc 27 in the direction of the arrow zof Fig. 3, strikes its endupon the tooth 36, which disconnects it from the wheel 23 thus breakingthe connection between the wheels 19 and 11. The stroke of the spindle34 is limited by a pin 40 which strikes against one of the supports 35.When the electro-magnet is enerized, it attracts the armature 37 drawingack the spindle 34, so that the tooth 36 meets no longer the end of thelever 25 which therer fore can proceed further remaining coupled withthe wheel 23.

The energization of the magnet 38 takes place at each turn of the wheel19, correspondingly to the passage, in the projection machine, of acertain number of pictures conveniently determined, i. e., 25 or 30pictures.

' The switch which breaks off the circuit is controlled by thegramophonical machine, every time it has turned by an angle whichcorresponds to the recording of the sounds within the time of thepassage of the 25 ojr 30 pic Assumed that the gramophonical machine hastwo disc carriers working alternately',the arrangement of the circuitmay be that shown Fig. 4.

On each of the two shafts 41', 41" of both gramophones is connected adlsc 42.,42,

the movement shown by the arrow was shown in the figure. Thus when thedies 42' begins again movement, the contact 43' meets immediately thecontact 48'. Each turn of one of the discs 42, 42", corresponds alwaysto the same number of pictures on'the film.

The number ofpicture s already projected is at every moment marked bythe hand 17 on the graduation not shown of the disc 18 for, as itresults from the foregoing description, the shaft 10 011 which aremounted the pinion 12 and the wheel 11 moves together and in theprescribed speed ratio on one hand the shaft 15 of the hand 17 by meansof the wheel 14, and on the other the shaft 7 of the projecting machinethrough the pinion 13. All the above premised it is now easy tounderstand the working of the whole device Assumed that the gramophoneconnected with disc 42" be in operation, that is to say that theelectrical connections are in the conditions'shown in Fig. 4, so thatthe disc 42 is speed than'the wheel20. Consequently, as

the ratchet wheel 23 by means of the lever 25 carrieswith it the disc 27and the latter. with its tooth 29 carries along with it. the wheel 11,the wheel 11 moves at a higher speed than the wheel 20 which lagsbehind, which it is allowed to do,by the riding of the yielding teeth 32uponthe crown 31. In this period the transmission of the movement theshaft 7eonnected to the projection ma chine, happens through thecoupleof' gears from the pulley 5 connected to the motor, to

21, 19, while the couple 22, 20 remainsinoperative.

When, advancing in its rotation the moving contact 43' arrives againstthe stationary contact 48(, whlch happens when 'the gramophone disc hasrotated enough for its. point to have covered the arc corresponding" tothe numberQof' pictures assigned, the electro-magnet 38 is. energizedand" withdraws the spindle with the tooth and in this withdrawal of thetooth 36 occurs just when it reaches the position to meet the end of thelever 25 and therefore the latter passes on freely keeping the sameconnection between wheel 19 and wheel 11 and the speed of theprojecting, machine remains unchanged.

As soon as lever 25 has proceeded further, the contact 4348 is brokenoff, the electro-magnet -becomes inoperative and the electrical andmechanical connections remain in. their former state during anotherrotation of the disc 42". j

If the film anticipates, that means that the shaft 7, and therefore thewheel 19 which transmits the movement to it, rotates'faster than thedisc 42 and therefore the end of lever 25 will meet the tooth 36 a shorttime before the latter has been withdrawn. During that short time, thatis to say until the tooth will become withdrawn the lever becomeswithdrawn, thus releasing the connection with the disc 27 which stopsand does not drive any longerthe wheel 11 with the tooth 29; But in suchconditions the wheel 11 is brought forward by the teeth 32 at the lowerspeed of the gear ratio, therefore the film totally or partially losesthe leadit had in respect to the gramophone. Then the tooth 36 will bedrawn back, thereby beingreinstated the condition between the wheels 1911, but the speed of .the film will not increase instantly once more.The increase of the speed of the film will take place only when thetooth 29 reaches again the tooth 30, which in the meanwhile isprogressing with the lower speed.

The third of the three cases mentioned I above, that is, the case of thefilm lagging 'behind, can'never occur, because the arrangement is suchthat the film. always anticipates in respect to the gramophone so thatthe lever 25 meets the tooth 36 at every rotation of the wheel 19.

In practice the durationof one turn and the difference for the twospeeds due to the pinions 21, 22, are chosen in such manner .that theequalization of the difference of phase when the lattershould arise, iseffectuated in only oneturn, that is in a time which is practically lessthan one second.-

' Inasmuch as the pinion 12 is, like the wheel 11, keyed upon the shaft10, thus whatever he the transmission ratio. thehand 17 always movessynchronically with the film and shows :the numbers of thepicturesjpassed, The disc of the gramophone is connected with anindicator, not shown, which gives the number of U the correspondingpicture in the film; in this way any lack of synchronism between the twomachines may be easily noticed by the operator.

I claim: 1

1. In a synchronizing device for a gramophone and a projecting-machine,both driven by a single motor, a'two ratio speed gear interposed in thetransmission and adapted to drive the projecting machine, said ratiospeed gear comprising a mofiomdriven shaft, a shaft interposed betweenthe former and the shaft of the projecting machine, sa toothed wheelsecured on said interposed shaft, a pinion on the shaft of theprojecting machine and with which the toothed wheel meshes, two gearwheels loosely mounted on the said inter- ,pose'd shaft, two pinions ofdifferent diameters on the motor driven shaft and with which the saidloose wheels mesh, a yielding means for connecting one loose wheel withthe.

toothed wheel, said yielding means being between the lower speed wheeland the said toothed wheel, a ratchet device for connect? ing the otherloose wheel with the-toothed wheel, and means capable of temporarilyreleasing the ratchet connection upon a lack of synchronism between thetwo machines.

2. In a synchronizing device for a gramophone and a projecting machineaccording to claim 1, the yielding connection between the lower speededwheel of the two ratio speed gear, consisting of a crown wheel on thetoothed wheel and two teeth each secured to a spring plate on the saidspeed wheel and passing through the same, said teeth being.

adapted to operatively engage .the crown wheel or to ride upon the sameaccording to which of the speed gear wheels the toothe 1 wheel is underthe action thereof.

3. In a synchronizing. device for a gramophone and a projecting machineaccording to claim 1, theratchet device between the toothed wheel andthe higher speeded wheel,

consisting of ratchet wheel integral with said speed wheel, a loose discon the shaft of the said wheel between it and the toothed wheel andprovided on one side with a tooth, the toothed wheel being provided with.a

tooth with which the tooth of the diSc'en gages, and a pivoted andspring pressed lever on the other side of the disc-and provided with atooth engaging the ratchet .wheel.

4. In a-synchronizing device for a gramophone and a projecting machine,a motor driven shaft, provided wlth pinions of differother speed wheel,a loose disc on the said 'shaftbetween the ,said'speed wheel and thetoothed wheel, a spring lever on the said loose disc and provided with atooth engaging the spring tooth from said path at every rotation" of thegramophone disc.

5. In a synchronizing device for a gramophone and a pro ecting machineboth drlven by a single motor, a motor driven shaft having pinions ofdifferent diameters thereon, a high speed gear wheel, a low speed gearwheel, both loosely mounted on a shaft interposed between said motordriven shaftfan d the projecting machine shaft, said gear wheels meshingwith the .pinions, a toothed wheel, geared with the shaft of theprojectingmachine, a yielding connection between the low speed wheel andthe toothed wheel, a

ratchet connection between the other speed wheel and the toothed wheeland including a pivoted lever, a disc carrying said lever, a

tooth in the path of the lever for lifting it at every rotation of thedisc to break the ratchet connection, a disc on the shaft of thegramophone, driven at a speed intermediate that of the high and lowspeed wheels, and means for withdrawing the tooth at every completerotation of the gramophone disc,

whereby the lever does not meet the said tooth when the projectingmachine is rotating at the same speed as the gramophone or is laggingbehind, but meets it when the projecting machine is running faster thanthe gramophone.

6. In a synchronizing device according to claim 5, a spring constructionfi or holding said tooth normally in the path of the lever, anelectro-magnet comprising said withdrawing means for operating thetooth, an electric circuit, a stationary contactand a disc on the shaftof the gramophone and carrying a contact adapted to meet the stationarycontact at every complete rotation of said disc to close the circuit andwithdraw the said tooth.

In testimony whereof I have aflixed my signature this 2nd day of July,1924. LUIGI ROBIMARGA.

